Currently, the research status is as follows: 1) single-agent PD-1 blockade has become the standard treatment for metastatic melanoma, 2) combining PD-1/PD-L1 blockade with CTLA-4 blockade or targeted therapy results in improved efficacy and increased toxicity, 3) neoadjuvant or adjuvant PD-1 blockade reduces the risk of recurrence; dual-ICB offers either better efficacy or increased toxicity, and 4) ACT is usually used as a salvage treatment for refractory metastatic melanoma, whereas T-VEC is usually administered as an adjunct to ICB. This evidence concerns the gene CTLA4 and metastatic melanoma.